# Power Systems Engineering (Elec-B7) - Solutions

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Next Technical Exam Sitting: May 11-15, 2020

Your exam is fast approaching.  You might be working a job and have a family that needs your time.  The last thing you want to do is spend \$1,000 on a course to re-learn this material.

If that sounds like you, our Power Systems Engineering (Elec-B7) help is for you.

About: The power systems engineering exam is written nationally for electrical aspiring engineers.  The code for this exam is:

• Electrical - 07-Elec-B7 (or you may see it like YY-Elec-B7, Elec-B7)

The exam tests candidate’s understanding and knowledge of power system analysis, components, distribution, fault analysis and system stability.

Format: 3-hour long, open book exam. Out of the seven questions that are asked in the exam, only five need to be attempted.

Dates written: The exam is offered twice every year in the months of May and December.

Approved aids: Since the course is highly computational, any non-communicating calculator is permitted.

After reviewing several previous exams, a pattern in the questions emerges.  Here is a summary of the different question types.

## Question no. 1: Transmission Line parameters

The first question tests your knowledge and your concepts about Transmission line circuits. It is a numerical question. You will be asked to convert, for example, the A1 and B 1 parameters to equivalent pi network Z1 and Yi and to Reduce the two parallel lines to one equivalent line represented by Zeq and Y and Determine the values of voltage, phase angle, active and reactive power. Power load at bus in per unit values at given p.f will be provided. All power formulae will be given with bus I being the reference with phase angle in the appendix  (Your deep understanding of  Transmission line Parameters, line impedance, Transmission line Impedance,  single line diagram, analysis, voltage magnitude and angle, Active and Reactive Power, Transmission line Modelling for short, medium and long lines, Transmission Line steady state operation and Transmission Line Steady state control voltage  will be tested here.

## Q2: Power system Analysis (Synchronous machine model)

The second question is a combination of theory and numerical. The theory tests your knowledge on the importance of reactive power in electrical power system and synchronous machines. Numerical Portion of this question will ask you to calculate active, reactive power, power angle and maximum power for given operating conditions. The synchronous machine such as generator will be connected to the infinite bus in the question. This question is approached by using your knowledge of synchronous machines and per unit system.

## Q3:Power Flow Analysis (Transformer Model)

Question three is regarding transformer modelling. You will be asked to describe different types of transformers and equivalent circuit. The numerical portion of this question will ask you to calculate the equivalent circuit parameters either referred to primary or secondary side, efficiency and voltage regulation of the transformers. The question is approached by theoretical knowledge of transformers and transformer modelling analysis.

## Q4:Bus impedance matrix, Transformer model, Synchronous model

The fourth question is also a numerical problem. It tests your bus impedance matrix, kVA rating, voltage ratio and the frequency for the transformers. You will be asked to find parameters for open circuit test from LV side and parameters for Short Circuit test from HV side. You will be asked to calculate the active power (P) and reactive power (Q) at the bus available in the system. You will be given data such as voltage, power angle, and impedance of the element. This question approached by using your knowledge of bus impedance matrix, transformer model and synchronous model.

## Q5:Short circuit Analysis, fault analysis for symmetrical and Asymmetrical system

The fifth question consists of short circuit analysis, fault analysis for symmetrical and Asymmetrical system. This question specifically tests your knowledge on the consequences of short circuit faults on power systems, protection schemes for transformers. For a given short circuit at given point/bus in a single line diagram, you will be asked to calculate fault current at bus / point in the circuit. Additionally, you will be asked to calculate the voltages at the specified bus under fault conditions.

## Q6: Sequence Networks

This question specifically tests your knowledge on sequence network (positive, negative and zero sequence network). You will be given a single line diagram and for a fault at given a point in the single line diagram you will be asked to calculate the fault current at a bus in the single line diagram. You may also be  asked to verify the sequence network of the system for a given single line diagram having components such as generator, transformer, bus, circuit breaker and transmission line with given parameters.

## Q7. Power system stability

This question specifically tests your knowledge on power system stability. You will be given a single line diagram having components such as a generator, transformer, bus, circuit breaker and transmission line with given parameters. For a given fault at a specific point in single line diagram, you will be asked to calculate initial power angle, power angle curve during fault clearing, post fault power angle curve and critical angle curve.

You could also be asked to calculate and check the system stability under given conditions.

The recommended textbooks for this exam are:

Based on your education and experience, we've put together a few different options to help you out.  If you are feeling confident in the material and believe you are knowledgeable on the exam topics, then a less expensive option may be best for you.  For those who need more help and support, the more expensive packages would be recommended.

\$350, \$250 Format: Solutions, support & course Skill level: All levels Language: English

Includes the following: (depending on your package):

• We'll provide solutions to two previous exams
• We'll provide you with email support for your technical exam questions

FEATURES

# Exam solutions

(Date of exam(s) solved)

Email support tickets

Length of access

Lite

\$250

1

(May 2018)

2

1 year

Solutions

\$350

2

(May 2018 & Dec. 2017)

5

1 year

Writing more than one technical exam? Following your purchase above, simply email us and we'll send you a discount code for 15% off any other technical exam product/service we offer.  Some people have to write multiple exams, so we want to make sure you don't spend a fortune on this licensing step.